From 3b7325f9485852243cc736cfaa1d6e6c0a5e148b Mon Sep 17 00:00:00 2001
From: Asbelos <asbelos@btinternet.com>
Date: Fri, 14 Aug 2020 09:41:14 +0100
Subject: [PATCH] Cleaner prog/main sync

Trying to reduce gap between prog and main signals when joined as a siding.
---
 DCCWaveform.cpp |  3 +--
 Hardware.cpp    | 16 ++++++++++++++++
 Hardware.h      |  1 +
 3 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/DCCWaveform.cpp b/DCCWaveform.cpp
index 9c317b5..20c5205 100644
--- a/DCCWaveform.cpp
+++ b/DCCWaveform.cpp
@@ -183,8 +183,7 @@ void DCCWaveform::setSignal(bool high) {
   if (progTrackSyncMain) {
     if (!isMainTrack) return; // ignore PROG track waveform while in sync
     // set both tracks to same signal
-    Hardware::setSignal(true, high);
-    Hardware::setSignal(false, high);
+    Hardware::setSyncSignal(high);
     return;     
   }
   Hardware::setSignal(isMainTrack,high);
diff --git a/Hardware.cpp b/Hardware.cpp
index df40a06..51a1e68 100644
--- a/Hardware.cpp
+++ b/Hardware.cpp
@@ -64,6 +64,22 @@ void Hardware::setSignal(bool isMainTrack, bool high) {
   if (pin2 != UNUSED_PIN) WritePin(pin2, high ? LOW : HIGH);
 }
 
+void Hardware::setSyncSignal(bool high) {
+  // This sets the same signal down both tracks at the same time.
+  // Speed notes.... 
+  // Objective is to get the two track signals to change as close as possible
+  // the high ? HIGH:LOW will only be evaluated once
+  // The UNUSED_PIN check will be done at compile time.
+  // If even more speed is required, its possible (not SAMD) to pre-prepare the
+  // DIO pinnumber->pincode translation so the WritePin (digitalWrite2) does not
+  // have to calculate the register and bit numbers every time.
+     
+  WritePin(MAIN_SIGNAL_PIN, high ? HIGH : LOW);
+  WritePin(PROG_SIGNAL_PIN, high ? HIGH : LOW);
+  if (MAIN_SIGNAL_PIN_ALT != UNUSED_PIN) WritePin(MAIN_SIGNAL_PIN_ALT, high ? LOW : HIGH);
+  if (PROG_SIGNAL_PIN_ALT != UNUSED_PIN) WritePin(PROG_SIGNAL_PIN_ALT, high ? LOW : HIGH);
+}
+
 int Hardware::getCurrentRaw(bool isMainTrack) {
   // tooo much crap for a interrupt routine. Will see how that goes.
   byte faultpin = isMainTrack ? MAIN_FAULT_PIN : PROG_FAULT_PIN;
diff --git a/Hardware.h b/Hardware.h
index 4c86a70..2362741 100644
--- a/Hardware.h
+++ b/Hardware.h
@@ -24,6 +24,7 @@ class Hardware {
     static void init();
     static void setPower(bool isMainTrack, bool on);
     static void setSignal(bool isMainTrack, bool high);
+    static void setSyncSignal( bool high);
     static unsigned int  getCurrentMilliamps(bool isMainTrack, int rawValue);
     static int  getCurrentRaw(bool isMainTrack);
     static void setBrake(bool isMainTrack, bool on);